1. Field of the Invention
The present invention relates to improved tire inspection equipment, and more particularly to an apparatus for inspecting the tire for defects during the curing process of a retread tire.
2. Brief Description of Prior Art
Tires have been retreaded for several decades according to a variety of methods. Retreading tires provides an economical way to gain additional use of a tire casing after wearing of the original tread.
In tire retreading operations, the worn tread is first stripped or buffed from the crown of the tire carcass in order to produce a surface suitable for bonding a new tread layer. A bonding layer and a new tread layer are built about the circumference of the buffed surface. In particular, the new tread layer is wrapped about the circumference of the tire casing over the bonding layer forming a retread tire assembly. The tire assembly bonding layer and new tread and carcass can then be placed within a flexible rubber envelope. The entire envelope, with the tire assembly disposed therein, can be placed within a curing chamber, i.e., an autoclave, and subjected to elevated pressure and temperature for a predetermined period of time. The combination of exposure to elevated pressure and temperature for a duration of time binds the bonding layer to both the tire casing and the new tire tread.
An autoclave is a large pressure and temperature controlled vessel having a capacity for several tire assemblies. In the autoclave, the tire assemblies are subjected to heat and pressure for a specified period. The chamber is normally heated to approximately Two Hundred Ten degrees Fahrenheit (210° F.) to Two Hundred Sixty degrees Fahrenheit (260° F.) and normally pressurized to approximately Eighty (80) psig to Eighty-Five (85) psig. An exhaust fitting of each tire assembly is individually connected to a hose that allows the pressure at the interior of the envelope to be controlled. The combination of pressure and temperature over time cures the bonding layer, permanently bonding the new tread to the casing.
The autoclave includes means for monitoring and controlling the amount of pressure the tire assemblies are subjected to inside the chamber, and further has means to control the temperature inside the chamber, as well as the time period the tire assemblies are subjected to the pressure and temperature. However, in the event an envelope having the tire assembly disposed therein has an air leak not detected, the new tire tread may not properly bond to the tire casing. Such problems can reduce the longevity of the retreaded tire and adversely impact application of the retreaded tire.
There is a need for an apparatus that eliminates the drawbacks in the conventional devices. In particular, there is a need for an apparatus and method that detects air leaks during the curing process for a retread tire. More particularly, there is a need for an apparatus and method that detects all leaks in the envelope and tire carcass, as well as the new tread and binding layer. The present invention fulfills these needs and provides further related advantages.